Microsoft is still running the Windows Insider Preview Program to give users the ability to have a look at new features and improvements before they will be released to the public. While the company has released a new build for the Release Preview Ring already this week, there is now new build available for users on the fast ring. However, while most builds are available for PC’s and phones at the same time, build 14977 released today is only available for mobile devices.

Donar Sarkar is also mentioning that we won’t get a new build of Windows 10 for PC’s this week because of a ‘blocking bug’ which could result in broken apps if you are upgrading to this build.

Windows 10 Mobile build 14977 isn’t bringing a lot of new features, though there is one included which you might know from the PC build released a couple of days ago. Microsoft Edge has received the feature to open ebooks directly in the browser which makes it easier to read ebooks in a specific file format. Any unprotected EPUB e-book can now be read in Microsoft Edge on PC’s as well as phones.

While there is a reading mode for websites which you can switch to in order to not being distracted, the e-book reading feature is a bit different. There is the ability to change the font size which is very helpful, you can even change the font to make it as comfortable as possible to read ebooks on your phone with your browser. Last but not least you can even choose from three different background colors while reading an e-book: light, sepia, and dark; and set a bookmark if you have to stop or search for a specific keyword if you want to continue to read.

What else has been changed?

Here is a list, taken from the official Windows Blog, which includes all minor fixes and changes which are coming with this build:

We’ve changed the rendering technology used for many types of UWP app content, so please provide feedback through the Feedback Hub if you notice any new visual glitches in UWP apps.

Alarms sent by 3rd party alarm apps will now break through Cortana’s Quiet Hours – we appreciate all the app developers who logged feedback requesting this, keep it coming!

We’ve removed the top-level option in Notification Settings to disable alarms on the lock screen – alarm reliability is a top priority for us, and we’ve found this setting was frequently enabled accidentally, without awareness that it would stop alarms from waking the phone when the phone was locked. For those who still wish to enable this setting, it’s will continue to be available under the per-app notification settings.

Notifications from Settings can now be customized or disabled – option is available under Settings > System > Notifications > Settings

We have enabled OAuth support for Yahoo Mail accounts. This will improve sync reliability for those accounts, and provide a secure experience while browsing your email.

We fixed an issue where disconnecting and reconnecting a wired headset while watching a video might result the audio no longer working.

We fixed an issue Insiders may have experienced where certain music apps would unexpectedly stop playing music after a single song.

We fixed an issue where closing a tab in Microsoft Edge, exiting the app, and then relaunching it would sometimes result in Edge opening to a blank page with the closed tab’s web address in the URL bar.

We fixed an issue where the Start Settings page wasn’t rendering when opened on external screen while using Continuum.

We’ve made a number of translation improvements, including, for French (France and Canada) speakers, fixing a grammatical error in the “Don’t Forget!” text seen when shutting down the phone so it now says “N’oubliez pas”, and for Chinese speakers, fixing an issue where the option to clear the Chinese Input Method Editor’s input history was displaying in English rather than Chinese. If you see any other translations that aren’t as you’d expect, please log feedback – we’re listening!

We fixed an issue where, if the setting to show notifications above lock had been turned off, booting the device and immediately checking the Action Center while the phone was locked could result in the Action Center not displaying any notifications after the phone had been unlocked.

We fixed an issue Insiders may have experienced where the Camera app might not appear after using the hardware camera button while the screen was off or while on the Glance screen.

We fixed an issue where Bangla (Bangladesh) keyboard text prediction might stop working after entering character followed by a vowel mark.

Known Issues

Here is a list, taken from the official Windows Blogl, which includes all known issues which are coming with this build:

Please avoid attempting to install new languages, keyboards, and speech packs on your phone. There is a chance these downloads may get stuck and not finish downloading. If you have existing languages, keyboards, and speech packs installed – they will carry over when you update to new builds. You can use Windows Device Recovery Tool to go back to Windows Phone 8.1 or Windows 10 Mobile, install any languages, keyboards, and speech packs you need and then update to the latest build in the Fast ring as a workaround.

Windows 10 phones with 8GB of internal storage such as the Lumia 550 and 650 will likely receive an 0x800700b7 error when attempting to update to this build.